Density measurement of a cubic liquid crystal ANBC-22

Abstract

4'n-alkoxy-3'-nitrobiphenyl-4-carboxylic acids (denoted as ANBC-n, where n is the number of carbon atoms in the alkoxy group) are well-known for forming two types of cubic liquid crystalline phases labeled cubic D. The unit cell volumes of both phases decrease with increasing temperature; those cubic phases show a negative thermal volume expansion. To clarify this unusual behavior, in this work, the density measurement was carried out as a function of temperature for the n=22 homologue ANBC-22. It was found that the density decreases and thus the number of ANBC-22 molecules per unit cell decreases with increasing temperature in both regions.